In digital Direct to Home (DTH) system, the receiver in the customer premise consists of an antenna, a STB (Set Top Box) and a detachable Smart Card. Due to various technical, implementation and market driven reasons, the STB is tied to the service operators. That is, the same STB cannot be used interchangeably across the service providers of DTH services. This vertical market structure has disadvantages for end users and for service providers entering the market. End users would benefit from a horizontal market of open/interoperable systems, where devices and services can be obtained from several different providers.
Presently STBs are tied to the service provider; same STB cannot be used for receiving programs from different service provider. Smart cards are service providers specific complying with ISO/IEC 7816-1, 2, 3 Standards. That is all smart cards comply with the same physical and electrical characteristics. However the communication protocol between the Smart card and the STB is proprietary. One of the main hindrances to STB interoperability is that the Conditional Access schemes are different for different service providers and the implementation of STBs are specific to the conditional access methods. The CAS (Conditional Access System) is implemented partly in STB and partly in the Smart Card. Due to this reason the STBs are tied to the specific CAS and the service provider.